1. Field of the Invention
The present invention relates to network interfacing, and more particularly, to methods and systems for detecting a link status between network stations connected to a telephone line medium.
2. Description of the Related Art
Local area networks use a network, cable or other media to link stations on the network. Each local area network architecture uses a media access control (MAC) enabling network interface cards at each station to share access to the media.
Conventional local area network architectures use media access controllers operating according to half-duplex or full-duplex Ethernet (ANSI/IEEE standard 802.3) protocol using a prescribed network medium, such as 10 BASE-T. Newer operating systems require that a network station be able to detect the presence of the network. In an Ethernet 10 BASE-T environment, the network is detected by the transmission of a link pulse by the physical layer (PHY) transceiver. The periodic link pulse on the 10 BASE-T media is detected by a PHY receiver, which determines the presence of another network station transmitting on the network medium based on detection of the periodic link pulses. Hence, a PHY transceiver at Station A is able to detect the presence of Station B, without the transmission or reception of data packets, by the reception of link pulses on the 10 BASE-T medium from the PHY transmitter at Station B.
Efforts are underway to develop an architecture that enables computers to be linked together using conventional twisted pair telephone lines instead of established local area network media such as 10 BASE-T. Such an arrangement, referred to herein as a home network environment, provides the advantage that existing telephone wiring in a home may be used to implement a home network environment. However, telephone lines are inherently noisy due to spurious noise caused by electrical devices in the home, for example dimmer switches, transformers of home appliances, etc. In addition, the twisted pair telephone lines suffer from turn-on transients due to on-hook and off-hook and noise pulses from the standard POTS telephones, and electrical systems such as heating and air conditioning systems, etc. Hence, the 10 BASE-T technique of sending link pulse cannot be used in a home networking environment, since the link pulses cannot be distinguished from noise signals inherently present in home networking environments.